By "engine swap", are you talking about replacing like for like, or are you talking about introducing a drivetrain that did not originally come in the vehicle? You need to be looking for 2 completely different kinds of shops for those 2 completely different jobs, IMO.
I can't help you with what's in the Atlanta area. But if it's the first type (like for like), you should really consider tackling the job yourself. It's not that difficult, it's just time consuming, and it will be a great learning experience. Maybe some Atlanta-based Xwebbers could be convinced to come over on a Saturday and help.
If it's the second type, then you need to be looking for a mechanic that has some fabrication skills and is not just a parts changer. If you have local races (1/8 or 1/4 mile drags, roundy rounds, SCCA races at Road Atlanta, that kind of thing), then go there, talk to people, and find out who they use for race fab work if they outsource it. A lot of times, mechanics themselves will be involved in racing - my main mechanic here does the dirt track oval stuff. He's worked on my K20 X before, and I would trust him with it.
For the second type of engine swap, however, you need to have very deep pockets. I would not expect anyplace who knew what they were doing to quote less than about $6-7k for a drivetrain swap, and that's assuming you supply a good working drivetrain, and the engine fits well without cutting too much up. If they have to start hacking into framerails, etc., then I would want someone more familiar with the X. As Karl said, MWB would be the people for that job. They did my K20 swap, it took a very long time and it was not cheap. Neither was shipping to get the car there and back.
I say all this to come to this point. Since you are new to X's, why not take the time to learn and enjoy the car as it is for a while. If in the future you decide on the need for more power, you can decide then how to take that step. In the meantime, if you know that more power is part of the plan in the future, then you need to be upgrading other systems of the car now. Better brakes, coil over suspension, VW radiator conversion are some very good places to start.
Good luck and enjoy your car.